On November 29, 2013, the Environmental Protection Agency (EPA) finalized a suite of changes to the mandatory greenhouse gas (GHG) reporting rule; the changes were initially proposed on April 2, 2013, and go into effect on January 1, 2014. While updates were made impacting confidential business information and other technical or administrative changes, the most significant of the updates are the changes to previously used Global Warming Potentials (GWPs) for 26 GHGs. Many GWPs have been increased, which may increase the number of facilities subject to reporting requirements under the GHG mandatory reporting rule.
What are GWPs?
When it comes to the ability to trap heat in the Earth’s atmosphere, not all gasses are created equal. Global Warming Potentials, or GWPs, are values used to adjust GHG emissions for gases that are more efficient at trapping heat than others. Emissions are multiplied by the appropriate GWP to calculate CO2 equivalents, or CO2e.
Changes to Table A-1
EPA has updated the GWPs based on values provided in the Intergovernmental Panel for Climate Change (IPCC)’s Fourth Assessment Report. EPA finalized the following changes to Table A-1, which lists the previous and updated GWPs for 23 GHGs:
|Name||Chemical Formula||Old GWP||New GWP||Net Change|
|HFC-134||C2 H2 F4||1,000||1,100||100|
|HFC-143||C2 H3 F3||300||353||53|
|HFC-143a||C2 H3 F3||3,800||4,470||670|
|HFC-236fa||C3 H2 F6||6,300||9,810||3,510|
|HFC-245ca||C3 H2 F6||560||693||133|
|HFC-43-10mee||CF3 CFHCFHCF2 CF3||1,300||1,640||340|
Any facilities or suppliers that become subject to GHG reporting as a result of the change in these GWP values must commence the required recordkeeping and monitoring on January 1, 2014 and report in March 2015. Furthermore, operators that become subject to the GHG reporting rule as a result of these changes may utilize “Best Available Monitoring Methods” (or BAMM) until March 31, 2014; any requests to extend the use of BAMM must be submitted to EPA no later than January 31, 2014.
Reporters that are already subject to the reporting rule must use these updated GWPs in their calculations, which are due for submittal to EPA no later than March 31, 2014.
Republication of Existing Reports
In the preamble, the EPA clarified that reporters will not be required to revise GHG reports from previous years with the revised GWPs from this rulemaking action. Instead, EPA will publish a supplemental version of the CO2e emissions for reporting years 2011 through 2012 that will not supersede any of the submitted data. This will, “allow the Agency and public to view and compare trends in GHG data…without placing additional burden on reporters.”
 Federal Register, November 29, 2013; Page 71937